1. Field of the Invention
This invention relates in general to the production of storage devices, and more particularly to a method and system for reducing production cycle time of a hard disk drive and a generic hard disk drive ready for customization.
2. Description of Related Art
The modern assembly line stems form the method of manufacturing first introduced by Eli Whitney in 1799 based upon the ideas of division of labor and of engineering tolerance, to create assemblies from parts in a repeatable manner. This linear assembly process, or assembly line, allowed relatively unskilled laborers to add simple parts leading to production of an end item. As all the parts were already made, they just had to be assembled. The assembly line also enabled manufacturers to build large quantities of identical products, to increase the rate of production and decrease the per-unit production costs.
An assembly line divides the assembly process into a series of processing steps through which the work-in-process moves until an end product is produced. These steps may be optimized, and once the manufacturing system becomes operational, the manufacturing system will build a number of products with the same configuration using the optimized steps.
Assembly lines are typically used in a built-to-stock production model, where large quantities of identical products are manufactured in anticipation of forecasted demand. The manufactured products are then warehoused until that demand is realized. Built-to-stock manufacturing systems are therefore primarily suited to markets in which manufacturers can accurately predict customer demand.
However, predicting customer demand is risky, at best. For example, in the market for computer systems and related items, technological improvements are realized so frequently and component prices change so rapidly that it is difficult to accurately predict how large the market for any particular product will ultimately be. As a result, when manufacturers in industries like information technology utilize the build-to-stock model, those manufacturers frequently find themselves with stocks of products that are difficult or impossible to market at a profit, i.e., outdated inventory.
Another production model that helps manufacturers avoid the stale-inventory problem is the built-to-order model. According to the built-to-order model, each product is assembled only after a customer has ordered that particular product. One of the disadvantages traditionally associated with the built-to-order model is that more time is required to fill orders, i.e., products must be manufactured, not simply taken from stock. Another disadvantage is that built-to-order manufacturing systems are typically less efficient than built-to-stock manufacturing systems. This drives up the cost of products that are built to order.
Some manufacturers have attempted to minimize the delays associated with the build-to-order model by maintaining a significant inventory of the components required for production, e.g., the components that are assembled to create the finished goods. Maintaining such an inventory, however, imposes costs on the manufacturers, including the costs associated with warehousing the material. Furthermore, in markets where product innovations occur rapidly, such material oftentimes become outdated.
When building an assembly line, various restrictions and sanctions come into play, depending on the product being manufactured and management policy. A hard drive assembly line is no exception. Rather, hard disk drive development is a very competitive business. The useful lifespan of a drive is only about 2 years. Thus manufacturers are unwilling to spend a lot of money on equipment. Moreover, clean rooms are extremely expensive to construct.
During hard disk drive assembly, the main components include a spindle assembly in which a number of disks are stacked at even intervals and fixed to an in-hub type spindle motor, an integrated actuator assembly in which there are a number of magnetic heads and an equal number of voice coil motors (VCMs), a frame, an upper frame cover, bushings which secure the spindle assembly to the frame, and covers for holes opened in the sides of the frame.
Today customers are requesting shorter production cycle times starting from hard disk drive (HDD) order placement to order completion for delivery. However, each manufacturing step for a HDD takes a certain cycle time. In general, HDD manufacturing requires eight steps: 1) parts cleaning; 2) assembly at the clean room; 3) servo track writing on the disk; 4) leak testing; 5) card assembly; 6) function test; 7) stress test and 8) packaging. The cycle time assumes availability of a set of components and capacity to support the above process steps. The component and capacity are planned according to monthly demand forecasts. However, mismatch between the monthly demand forecast and customer orders add three months of more additional cycle time for long lead-time components and to setup capacity.
In addition, manufacturing may have completed HDD inventory that has functions that satisfies another customer. However, the manufacturer cannot ship the HDD because the HDD was assembled using a different specification, e.g., microcode or label. The personalization of the HDD occurs at the assembly at the clean room. This mismatch situation occurs due to differing order activity. Thus, such a HDD becomes idle inventory unless reworked to meet a different specification.
It can be seen then that there is a need for a method and system for reducing production cycle time of a hard disk drive and a generic hard disk drive ready for customization.